Concrete Pier of Old Bay Bridge to Be Imploded

Bay Bridge San Francisco (Frank Schulenburg / Flickr / CC / Cropped)
Frank Schulenburg / Flickr / CC / Cropped

On Saturday, November 7, at 9 a.m., Caltrans work crews will implode the largest concrete pier of the old Bay Bridge eastern span, a five-story underwater structure.

The San Francisco Chronicle reported that the implosion will cost $160 million. The Chronicle quoted San Francisco Oakland Bay Bridge spokesperson Leah Robinson-Leach telling KBCW, “Had we utilized another method, a mechanical or traditional method, as is known, we would have been in the bay for months, potentially years, having a far greater impact to the environment. The reason we are imploding the pier; it will actually drop into those caissons. They’re watertight structures that are actually hollow.”

A blast mat over the top and a bubble curtain around the area to the bay floor will keep the debris from the five-story, 20 million-pound tower from falling into the bay.

Caltrans received permission from the U.S. Army Corps of Engineers in early October, after the agency stated that imploding the structure would “significantly reduce impacts to the environment,” compared to the original $254 million demolition plan, which would have entailed damming the area around the pier for at least a year while utilizing special mechanical saws and heavy equipment.

The demolition of the 77-year old East Span section-by-section of the old Bay Bridge began in 2013, and was planned to have three stages. The underwater foundations would be destroyed as the last step.

The East Span of the old Bay Bridge ran 1.97 miles, with 58,209 tons of steel and 245,470 tons of concrete.

The demolitions are unrelated to the corrosion problems on the adjacent new Bay Bridge, which have become an ongoing scandal and may shorten the engineering lifespan of the structure.